Fortia

This force simulates the Lennard-Jones potential. There are three parameters for this force:

- depth: The minimum value of the Lennard-Jones potential well
- rmin: The distance from the origin to the minimum of the potential
- cutoff: The distance, where the Lennard-Jones (LJ) potential is often truncated to save computational time

These parameters are empirical and are usually obtained from experiment or some rough estimation.